Internal combustion engines include cooling systems for removing excess heat that is produced from the combustion of fuel and friction of moving components. Removal of the excess heat is necessary to prevent the mechanical failure of engine components. The cooling systems typically include a liquid coolant that is pumped through passageways (sometimes known as water jackets) in the engine block, cylinder head, and other engine components. Heat is transferred to the liquid coolant from the engine components when the coolant flows through the various passageways in the engine components. Heat is then transferred from the liquid coolant to the surrounding environment through a heat exchanger, such as a radiator. Once the heat is transferred to the surrounding environment, the liquid coolant is redirected through the passageways in the engine components and the process is repeated.
An internal combustion engine having cylinders that share a common wall is known as a “Siamese design” and the common wall is known as the “bore bridge.” The bore bridge will experience high temperatures because it is in close proximity to the two combustion chambers of the adjacent cylinders, and to the two sets of piston rings that transfer heat to the cylinder block. Packaging of a cooling system in the area of the bore bridge is also difficult adding to the increased temperature of the region.
Various efforts have been made to cool the bore bridge. It is known to drill cooling channels within the bore bridge that extend between the water jacket in the engine block and the cylinder head. This configuration presents limitations in the flow of the liquid coolant through channels in the bore bridge because of a limited pressure differential and channel cross sectional area.
It would be desirable to provide a cooling channel in the bore bridge that has an adequate pressure differential and flow area to allow liquid coolant to sufficiently flow through the channel.